Fuel supply apparatus



P 1968 J. c. MCALVAY 3,402,733

FUEL SUPPLY APPARATUS Filed April 6, 1967 Jaz/ 12 United States Patent3,402,733 FUEL SUPPLY APPARATUS John C. McAlvay, Racine, Wis., assignorto Webster Electric Company, Inc., Racine, Wis., a corporation ofDelaware Continuation-impart of application Ser. No. 562,908,

July 5, 1966. This application Apr. 6, 1967, Ser. No. 628,990

12. Claims. (Cl. 137-467.5)

ABSTRACT OF THE DISCLOSURE The apparatus provides for automatic purgingof air from a single pipe supply system and manual purging (by openingof an air vent) of a two pipe type system combined with high lift andfast cut off. A pump supplies oil through flow out off-pressureregulating means, such as a duplex valve, as to a burner nozzle. A firstflow restricting bypass is connected across the pressure regulatingmeans and a second but less restrictive bypass including normally closedvalve means is connected effectively across the pump, preferablydirectly across the pump outlet and inlet means, the latter being eitherthe pump inlet or the pump inlet chamber with filter means thereinsupplying the pump inlet. Alternatively, the second bypass may beconnected across the outlet and a return line from the pressureregulating means.

This application is a continuation-in-part of application Ser. No.562,908, filed July 5, 1966, by John C. McAlvay, and assigned to theassignee of this application, now abandoned.

The present invention relates to fuel supply apparatus and has for itsprimary object the provision of new and improved apparatus particularlyadapted for supplying oil to oil burners.

Fuel supply apparatus of the type to which the present invention relatesare generally known as fuel units and customarily include an electricmotor driven gear type oil pump, a pump inlet chamber comprising afilter, and cut off and pressure regulating valve means, such as aduplex valve, the motor generally also driving a fan supplying air tothe burner nozzle. The valve is supplied from the pump outlet andperforms primarily two functions, i.e., controlling the fiow of oil to autilization outlet and regulating pressure by causing excess oil to flowto an excess flow outlet adapted selectively to be connected by a returnline to the pump inlet chamber in a one pipe system and to a source offuel such as a fuel tank in a two pipe system.

Difficulties have been encountered with this type of apparatus uponstart up, i.e., when first placed in operation after installation orservicing, particularly when used in connection with small heating unitshaving a restricted flue passageway which disturbs combinationcharacteristicsto such an extent that fuel units operatingsatisfactorily elsewhere will not do so when, for example, they areinstalled in arrangements requiring a high lift of twenty feet or so.Such a high lift is required, for example, when the fuel supply inletline is arranged in an inverted somewhat U-shaped configuration from theoil tank to the pump with the tank and pump located considerably belowthe topmost point of the line and with the tank lower than the pump.Further complications arise from a requirement for quick purging of air,for fast cut off of the flow of oil to the nozzle when the pump motor isdeenergized, and for purging of air from the apparatus to be effectedautomatically when the two pipe connections are used. Manual ventingthrough a manually opice erable vent valve is considered satisfactoryfor one pipe operation. If purging of air from the apparatus does nottake place in a relatively short period of time, safety devices wiilde-energize the motor.

Avoidance of disturbances in combustion characteristics is generallyachieved by providing the pressure regulator with a bypass. Some havebeen provided with a small area bypass, generally called a standard slotand others, to achieve a fast cut off, with a larger area bypass,generally called a deep slot. However, the deep slot construction, whileproviding desirable faster cut off, offers so little restriction to airpassage that even a modest lift, e.g., less than the mentioned oftenrequired lift of twenty feet or so, will result in recirculation of airthrough the pump rather than the air being expelled through the manuallyoperable vent valve in two pipe operation. A standard slot provides highlift but not sufficiently fast cut off.

Attempts have been made to overcome the aforementioned difficul'ties.Passages with normally closed check valves have been connected acrossthe pump outlet and return line or across the pump outlet and pump inletchamber. Both of these arrangements have utilized a pressure regulatorvalve having no additional bypass. Other attempts have involved the useof normally closed check valves in the return line from a pressureregulator valve having a standard or deep slot associated therewith.However, the various arrangements of the prior art did not provide highlift on single pipe operation and automatic purging on two pipeoperation in combination with fast cut off.

An object of the present invention is to provide a new and improved fuelsupply apparatus comprising a fuel supply pump and cut off and pressureregulating means constructed and arranged to operate reliably withinshort time limits in single pipe and two pipe installations, and whichprovide a high lift, purges air automatically in two pipe operation,provides fast cut off of the fuel as to a utilization outlet and burnernozzle when the demand for oil is terminated, and which reduces thequantity of oil that needs to be filtered.

In brief, the fuel supply apparatus of the present invention is adaptedfor both single and two pipe operation and provides high lift, automaticpurging of air from the apparatus in two pipe operation, manual purgingin single pipe operation, fast purging of air, fast cut off of the flowof fluid, such as oil, to a utilization device which may be an oilburner nozzle, for both one and two pipe operation, and reduces theamount of oil required to be filtered, as well as required to beobtained from a fluid reservoir in two pipe operation. The apparatusincludes a pump, which may be of the gear type and have a capacityexceeding requirements of the burner, and a valve of the duplex typecontrolling the flow of oil to the nozzle and the pressure at which theoil is supplied. Oil is supplied to the nozzle under control of the cutoff portion and the pressure is controlled by the pressure regulatorportion which returns excess oil through an excess flow return line tothe pump inlet chamber for single pipe operation and to a reservoir intwo pipe operation. The pressure regulator portion is effectivelybypassed by a passageway having a small area restricted orifice, i.e., astandard slot, in parallel with the pressure regulating portion, i.e.,across the pump outlet and return line. A second bypass with arelatively larger orifice and a normally closed check valve iseffectively connected across the pump outlet and pump inlet means, i.e.,to the pump inlet chamber directly to the pump inlet so there is no needto filter the recirculated oil. Alternatively, the second bypass can beconnected to the return line. The normally closed check valve and therelatively more restricted bypass across the pressure regulatingportion, which is dimensioned to maintain oil in it by capillary forceand to prevent the flow of air through it when the vent port is opened,prevent recirculation of air through the pump so that purging of airfrom the apparatus can be effected manually for a single pipe operationas upon initial start up or after servicing by opening an air vent portcommunicting with the pump outlet. After the purging the plug isreplaced and oil flows through both bypasses in normal operation.Purging is effected automatically for two pipe operation through therelatively more restricted standard slot bypass with the vent portclosed, as both oil and air fiow through it and the air is purged intothe reservoir. During this purging operation, the check valve maintainsits associated bypass closed. The check valve opens at a pressureslightly in excess of the pressure generated by the pump with air in thesystem, i.e., at a pressure somewhat above fifteen p.s.i., so that it isclosed for purging of air and thereafter automatically opens in responseto higher pressure generated by the pump when pumping oil.

Other objects and advantages of the present invention will becomeapparent from the ensuing description of illustrative embodimentsthereof, in the course of which reference is had to the accompanyingdrawing, in which:

FIG. 1 illustrates, largely diagrammatically, in embodiment of a fuelsupply apparatus constructed in accordance with the present invention;and

FIG. 2 is a fragmentary view of a second embodiment of the invention.

Referring now to FIG. 1, the apparatus of the present inventioncomprises what is generally known as a fuel unit indicated as a whole bythe reference character 10. It comprises an oil pump and duplex valvegenerally constructed as a unit. The pump 12 may be of the gear type andof a construction such as shown in Patent 2,966,118, McAlvay, grantedDec. 27, 1960, and driven by an electric motor that also drives a fansupplying air to the burner nozzle, the motor and fan not being shown.The duplex valve 14 itself is of conventional standard slot constructionand constitutes valve means controlling oil to a utilization outlet andregulating the pressure of the oil. The duplex valve is, however, in thecombination of the present invention made to provide a fast cut off ofthe flow of oil to the outlet line when the pump motor is deenergized,as will be described later.

The duplex valve includes a chamber or body 16 and a movable valveportion 18. A cut off portion 20 disposed at one end of portion 18includes a movable valve element 22 below a land 24 on the movableportion. Element 22 cooperates with a stationary valve seat 26 tocontrol the flow of oil to a utilization outlet 28 connected as byconduit 30 to an oil burner nozzle 31. The outlet is normally closed andis adapted to be opened at some desired pressure, such as about eightyp.s.i.

A pressure regulating portion 32 comprises a land 34 on the movableportion 18 that cooperates with an internal groove or slot structure 36in the body so that the pressure of oil supplied to the nozzle isregulated by causing more or less of the oil from the pump to flowthrough the groove structure to an excess flow outlet 38 connected topassageway 40 constituting an excess flow or return line. Adjustment ofthe pressure maintained by the duplex valve is effected by control ofthe compression of a spring 42 utilized to bias the movable valveelement 18 to its lowermost position, i.e., in a direction to maintainthe outlet 28 closed. As illustrated, the spring extends into a centralbore 43 within, and an end abuts, the valve portion 18. The upper end ofthe spring is secured to an abutment 44 adapted to be raised or loweredby adjustment of a thumb screw 46.

Purging of air from the apparatus on start up, i.e., when the apparatusis initially placed into operation or after servicing, is effectedmanually for the single pipe connections through an air vent valve 48effectively connected to the pump outlet and illustrated as beinglocated on the valve body 16. It communicates with a chamber 58, to bereferred to further and to which the pump outlet is connected.

The pump 12 has inlet mean-s indicated generally by the character 50 andan outlet 52. The latter is connected to and supplies oil to the duplexvalve, which has an inlet 54 connected by passage 56 to a chamber 58formed between the lands 24 and 34, which chamber is thus effectivelyconnected to the pump outlet and from which ex cess oil is supplied tothe excess oil line through groove structure 36.

The inlet means 50 may comprise an inlet chamber indicated by thereference character 50A generally constructed as a part of the fuel unitand including filter means (not shown) and through which filtered oil issupplied to the pumping chamber through a pump inlet passageway 51. Theterm inlet means is used herein in a generic manner to refer to the pumpinlet chamber 50 and the pump inlet passageway 51.

Fuel supply apparatus of the type to which this invention pertains isconstructed so that it can selectively be used for one or two pipeoperation. In one pipe operation the pump inlet 50 means is connectedthrough a supply line 64 to a source of fuel such as a fuel tank 66 andthe excess oil line 40 is connected through a manually operable and openvalve 68 to the pump inlet means. In many installations, and as showndiagrammatically, the supply line has an inverted U-shaped configurationand the fuel tank is lower than the fuel unit and the latter is lowerthan the high point of the line. In a two pipe operation the valve 68 isclosed and the return line 40 is connected by a return line 70 to thefuel tank. Actually, the fuel unit is, for the most part, constructed inknown manner so that all of the apparatus described above, withexception of the supply conduit 64 and the two pipe return line 70, arebuilt as a combined fuel unit and pressure regulator. The valve 68 isgenerally a pipe plug which may be inserted to disconnect line 40 fromthe pump inlet means for two pipe operation and which can be removed forsingle pipe operation.

In accordance with the present invention as illustrated in FIG. 1 and toprovide the advantages of reliability, high lift, especially on singlepipe operation, automatic purging under two pipe connections and fastpurging and fast cut off of the flow of oil to the oil burner nozzle,the system is provided with a flow restricting bypass of the deep slottype indicated as a whole by reference character 72 connected directlyacross the pump outlet 52 and the pump inlet means 50. It should benoted that, as illustrated in solid lines, the inlet means is the inletpassageway 51. However, the inlet means could be the inlet chamber 50A.The advantage of connecting the bypass 72 across the pump outlet andinlet passageways is that the recirculated oil is not filtered.Accordingly, less filtering capacity is required.

The flow restriction in bypass 72 is provided by an orifice 74 and itincludes a normally closed check valve 76, comprising a ball 76A andspring 76B, arranged to prevent flow from the outlet to the inlet meansbelow a predetermined pump outlet pressure such as about fifteen p.s.i.The check valve primarily prevents recirculation of air (and also ofoil) during purging of air from the apparatus but bypasses orrecirculates oil from the pump outlet to inlet means after purging hasbeen completed. The orifice is preferably between the pump outlet andthe check valve so that, when the valve is closed, oil is maintained inthe outlet side and orifice 74 in a manner akin to holding liquid in astraw by closing one end with ones finger. A check valve and orificeconstruction such as shown in the copending application of Louis J.Schwob, Ser. No. 562,656, filed July 5, 1966, now abandoned,

may be used when the bypass 72 is connected to the inlet chamber 50A.

A standard slot type of restricting bypass 80 is provided across thepressure regulating portion 32 of the duplex valve. It is illustrated asbeing in the valve body and effectively connected across the pump outletand return line 40. It could be located elsewhere, as in and through theland 34. As shown, it comprises a passageway 82 provided with a flowrestricting standard slot orifice '84 dimensioned to restrict flow ofair to an extent such that the apparatus may be purged of air on startup whena single pipe connection is utilized, the purging being effectedby opening the vent port 48. The orifice 84 is filled with oil at thefactory as during testing of the apparatus when oil flows through theorifice and is retained in it by capillary action. The retention is suchthat air will not flow through the orifice when the vent port is openedfor single pipe purging. In two pipe purging, as noted later, air willflow through the orifice and bypass at a pressure less than that atwhich the check valve 76 is opened. During the purging operation, thecheck valve 76 remains closed until the air is purged and the vent portclosed. Gear pumps, such as pump 12, generate an air pressure of lessthan about fifteen p.s.i., which is sufficient to discharge air throughvent 48 but insufficient to open check valve 7 6 or force anysubstantial amount of air through bypass 80. Automatic purging of theair is effected through the bypass 80 when the two pipe connection isutilized and the air vent valve is closed, the air being discharged at apressure of less than about fifteen p.s.i. generated by the pump throughthe bypass and the return line 40 which, in the two pipe operation isconnected to the oil tank through return line 70.

In a characteristic installation, the duplex valve 14 may be constructedand arranged to open the cut off portion at a pressure of eighty p.s.i.and supply from one to three g.p.h. to the nozzle. The pressureregulating portion may be adjusted to maintain a pump outlet pressure ofabout one hundred p.s.i. The pump should have a substantial output such,for example, as thirty g.p.h. The bypass 80 across the pressureregulating portion of the duplex valve may pass about four g.p.h. Thebypass 72 from the pump outlet to the pump inlet means may pass abouttwo to three times that flowing through bypass 80, i.e., eleven g.p.h.,and the check valve 76 may open at a pressure of about fifteen p.s.i.These values may obviously be varied dependent upon the size of the unitand the demands of a particular installation. The relationship betweenthe two bypasses must, however, be such that the check valve 76 not openuntil a substantial pressure has been developed at the pump outlet andthereafter a considerable portion of the pump outlet is bypassed throughline 72. As noted earlier bypass 80 across the pressure regulatingportion of the valve is dimensioned to prevent any substantial air flowthrough it when the vent 48 is opened but permits flow of air throughwhen the vent port 48 is closed and the two pipe connection utilized sothat automatic purging will occur in the two pipe operation. The reasonfor the pressure selected for the opening of check valve 76 is to insureit will not open to connect the pump outlet to the pump inlet means andthus recirculate air and oil at relatively low pump inlet or suctionpressures. 'If it did, then satisfactory lift could not be obtained. Thearrangement as described will effectively and reliably provide a highlift as of twenty feet or so when the single pipe connections are used,i.e., when the valve '68 is opened to connect the return line 40 to thepump inlet means 50. Also, fast cut off is provided because the pressureregulator valve handles only a relatively small quantity of oil so thatthe :cut off valve element 22 has to move but a small distance to closethe outlet when pump motor is de-ener-gized.

The present invention thus provides fast cut off along with the manyadvantages heretofore described. This is done in a simple manner by theprovision of the bypass 72 across the pump with the orifice and checkvalve means in it. Cut off of the flow of oil to the oil burn r nozzleoccurs at a sufficiently high pressure to insure proper atomization ofthe fuel delivered to the nozzle. The cut off takes place while the fanspeed is still high enough to supply an adequate volume of air foratomization of the oil. Accordingly, undesirable air-oil mixturessometimes occurring with previous arrangements are prevented.Furthermore, priming occurs sufficiently rapidly so as to be within thelimits of operation of flame saf ty devices ordinarily used, i.e.,within about one and one-half minutes. The bypass also reduces theamount of oil required to be supplied to the pump inlet from the tank intwo pipe operation. Also, less filtering is required when the bypass isconnected to the pump inlet passageway as the recirculated oil is notfiltered. The arrangement of the invention is not a compromise andprovides fast, effective and reliable operation for both one and twopipe systems.

All of the advantages set forth above, but for the lesser amount of oilrequired to be supplied to the pump from the tank and required to befiltered in two pipe operation, may be obtained with the modificationillustrated in FIG. 2. In this modification, the bypass 72 with itsorifice 74 and normally closed check valve 76 is connected across thepump outlet 52 and the return flow line 40. The only difference betweenthe arrangement of FIG. 1 and that of FIG. 2 is that in the former thepump has to lift only sufficient oil from the reservoir 66 through theinlet line 64 to make up the oil supplied to the nozzle. In the FIG. 2arrangemnt, the excess flow from the pressure regulator valve and theflow through the bypass 72 are both returned to the reservoir in twopipe operation, so

that more oil has to be lifted by the pump and filtered. The terminologywith respect to the valve bypass 72 being effectively across the pump isintended to apply to all three arrangements, i.e., where the bypass isconnected from the pump outlet to the return line, or to the pump inletchamber, or the pump inlet passageway.

Although the present invention has been described by reference toillustrative embodiments thereof, it will be apparent that numerousother modifications and embodiments may be devised by those skilled inthe art and it is intended by the appended claims to cover all suchmodifications and embodiments which fall within the true spirit andscope of the present invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. Fuel supply apparatus for supplying liquid fuel to oil burners andthe like through single pipe or two pipe connections including a fuelsupply pump having a capacity in excess of burner requirements and aninlet adapted to be supplied from a source of fuel and an outlet, valvemeans connected to and supplied from the pump outlet of the type havingcut off means controlling flow to a utilization outlet adapted to beconnected as to the nozzle of an oil burner and regulating means with anexcess flow outlet adapted selectively to be connected to pump inletmeans in a single pipe connection or to the source of fuel in a two pipeconnection and a normally closed air vent port effectively connected tothe pump outlet and adapted to be opened for purging air in a singlepipe connection wherein the improvement comprises a first flowrestricting bypass effectively across the pressure regulating means andrestricting flow of air to an extent such that the apparatus whenconnected for single pipe operation may be purged of air on start up byopening of the vent port, and permitting How of air and restricted flowof oil with the vent closed whereby automatic purging of air throughsaid first bypass is effected on start up of the apparatus when it isconnected for two pipe operation, and a second flow restricting bypasseffectively across the pump including a normally closed check valv meansmaintaining said bypass closed to prevent recirculation of air throughthe pump so that purging of air from the apparatus is effected throughthe vent port when the latter is opened.

2. Fuel supply apparatus as claimed in claim 1, wherein said check valveopens at a pump outlet pressure above the pressure generated by the pumpwhen air is present in the apparatus.

3. Fuel supply apparatus as claimed in claim 2, wherein said check valveopens at a pump outlet pressure somewhat higher than about fifteenp.s.i.

4. Fuel supply apparatus as claimed in claim 1, wherein said first flowrestricting bypass is dimensioned to retain oil in it by capillary forceand flow of air through it is prevented and the air is purged throughthe vent port when the latter is opened on start up with a single pipeconnection.

5. Fuel supply apparatus as claimed in claim 1, wherein said second flowrestricting bypass is dimensioned to provide a flow of fuelsubstantially greater than that through said first fiow restrictingbypass.

6. Fuel supply apparatus as claimed in claim 5, wherein the flow throughsaid second flow restricting bypass is on the order of two to threetimes the fiow of the second bypass.

7. Fuel supply apparatus as claimed in claim 4, wherein said second flowrestricting bypass is dimensioned to provide a flow of fuelsubstantially greater than that through said first flow restrictingbypass.

8. Fuel supply apparatus as claimed in claim 1, wherein said second fiowrestricting bypass comprises a flow restricting orifice between thecheck valve and the pump outlet.

9. Fuel supply apparatus as claimed in claim 1, wherein said second flowrestricting bypass comprises a flow restricting orifice located betweensaid check valve and the pump outlet and is dimensioned to provide asubstantial flow of oil such as about one-third of the total pump outputand wherein said check valveopens at a pump outlet pressure of aboutfifteen p.s.i., and wherein said first flow restricting bypass is.dimensioned to retain oil in it by capillary force and flow of airthrough it is substantially prevented when the vent port is openedwhereby the apparatus may be purged of air on start up when a singlepipe connection is utilized upon opening of the vent port with saidcheck valve remaining closed until the vent p-ort is closed, said firstbypass providing flow of air and restricted flow of fuel when a two pipeconnection is utilized whereby automatic purging of air through saidsecond bypass and theexcess flow line to the fuel source is effected onstart up of the apparatus.

10. Fuel supply apparatus as claimed in claim 1, wherein the secondfiowrestricting bypass is connected acros the pump outlet and pump inletchamber.

11. Fuel supply apparatus as claimed in claim 1, wherein the second flowrestricting bypass is connected across the pump outlet and pump inletpassageway.

12. Fuel supply apparatus as claimed in claim 1, wherein the second flowrestricting bypass is connected across the pump outlet and return line.

References Cited UNITED STATES PATENTS 2,037,994 4/ 1936 Neubauer158-363 2,209,856 7/1940 Smith et a1 103-42 2,931,314 4/1960 Erikson eta1 103-42 X 3,294,147 12/1966 Damon 158-363 X FREDERICK KETTERER,Primary Examiner.

